I realize this is a controversial topic, but I'd like to get some advice on resizing photos for large prints. I'm shooting a 5DII and have been cropping some of my landscape images down to a 1:2.5 aspect ratio.

I'd like to print images at 18x45 or 20x50, but at about 5616px on the long end, i'm looking at 112dpi.

I'm thinking about using something like perfect resize or blow up 3, but i'm not sure how "safe" it is to resize the images at 150% or 200%.

I've been reading the reviews out there, but I'd like to get some advice from someone how prints large from a 5DII or has used the tools.

It all depends on viewing distance and IQ expectations. Try it and see how well it works for your needs. I used genuine fractals for a long time with good results, but now the cameras have enough MP and I'm better with panos so I usually don't need it.

It's completely a matter of subject, original image, and personal preference. Blow some up a couple ways, print 'em, and decide whether any are good enough and which methods work best.

Blow Up and Perfect Resize both have fully-functional trials. If you don't want to print the full-size image (which admittedly may be cost-prohibitive), crop a representative or difficult section out of the enlarged files and print them as nice cheap 8x10s. Keep in mind the size of the full print when you're viewing them; if I'm showing test strips to someone else, I'll mark out the full size on the wall with spike tape.

Also don't be afraid to try adding grain either in the enlargement utility or in Photoshop or Lightroom—one of the great losses in the digital age is the "detail" and "sharpness" grain invents for you.

If you're going to inkjet, I'd include a more limited enlargement in your experiment. 180 ppi, though it doesn't sound like much, is often sufficient for modern inkjets to produce a decent result. Again if you're using inkjet, consider your paper choice; a textured paper offers the same effect as grain does. Combine the two and you can hide a lot of sins while producing a very attractive print.

You will need to decide for yourself if you like those relatively low resolution prints. For portraits and many other sorts of images, the prints are likely to be very acceptable. For landscapes where you want details, the quality of the prints are less likely to meet your expectations. Sounds like you should have shot these for stitched panoramas.

I'm different yet again. I've proven to myself an untold number of times that it's almost ALL about viewing distance and setting. 1ppi looks awesome from 300 feet away for example. I find that if the total resolution looks good at 80 to 100cm away then there is no limit at which you can print it - including the size of the Empire State Building or the state of texas. You just have to hang it far enough away that the relative size appears about the same as an A4 from 80 to 100cm away. 100 to 120 ppi should look fine tho - even when printed to an A4 sheet and held close.

With my experience the material printed on plays the biggest role when making large enlargements. I've made 6 meters wide prints from 16mp files, printed on canvas. They looked great. People look at them at half meter distance. Same files printed 1 meter wide for glossy high quality material doesn't look that great when looked at close distance.

I mostly just use photoshops "bicubic smoother" when enlarging. I find it better to have softer image than pixels showing up.
Enlarging software like Perfect Resize might work on some files but they tend to give a painterly look for everything.

I've never understanded the "viewing distance" thing because people have the tendency to stick they're nose pretty close to prints unless the prints are hanged very high or surrounded by barriers.

Sami Ruusunen wrote:
I've never understanded the "viewing distance" thing because people have the tendency to stick they're nose pretty close to prints unless the prints are hanged very high or surrounded by barriers.

That's where the "setting" comes into play. If you're hanging it on the walls of your staircase then people will poke their nose in. But if it's above the fireplace in a large living-room then they won't - unless your guests are the rude nosey type. :P

In a gallery the content can sometimes make the difference. If it's a detailed shot from far away of something like a cityscape which includes many tiny people (or something like that) then this content will invite folks to lean in. Whereas if it's a bust or something then normal people (those there mainly for art appreciation and viewing) will stand back where the image can be viewed.

And finally even if they do lean in and see pixels, fine, let them. No problem. If they wanna see pixels they're free to do so - like checking out the brush-strokes of a painting. It's only when the people want to stand at an optimal position for viewing /the image/ and are interrupted by pixelation that it's /a problem/.

Think of television. Sure you CAN sit too close and notice all the pixels but if you sit where you're supposed to (in a nicely designed viewing room) then it looks right. I can just hear my mom now: "Don't sit so close to the TV, you'll melt your brain!"

Think of television. Sure you CAN sit too close and notice all the pixels but if you sit where you're supposed to (in a nicely designed viewing room) then it looks right. I can just hear my mom now: "Don't sit so close to the TV, you'll melt your brain!"

I was able to find a local printer who'll work with me. I'm heading over there thursday and we'll take a look at the individual images and try a few test prints of detail areas at the target size. That should be telling. Most of what I shoot is landscape and architecture (so not portraits that will end up on a staircase - but you never know). I do like the TV analogy and there is definitely something to be said about viewing distance.

I'm hoping to see some samples on thursday of prints at different resolutions to help make a determination.

In the end, I'll be shooting a lot more stitched panos. I'll see what I can do with what I currently have though. I'm a bit leery of tools, but i imagine i should be able to enlarge to 150% safely. We'll see.

Think of television. Sure you CAN sit too close and notice all the pixels but if you sit where you're supposed to (in a nicely designed viewing room) then it looks right. I can just hear my mom now: "Don't sit so close to the TV, you'll melt your brain!"

Malux wrote:
I was able to find a local printer who'll work with me. I'm heading over there thursday and we'll take a look at the individual images and try a few test prints of detail areas at the target size. That should be telling. Most of what I shoot is landscape and architecture (so not portraits that will end up on a staircase - but you never know). I do like the TV analogy and there is definitely something to be said about viewing distance.

I'm hoping to see some samples on thursday of prints at different resolutions to help make a determination.

In the end, I'll be shooting a lot more stitched panos. I'll see what I can do with what I currently have though. I'm a bit leery of tools, but i imagine i should be able to enlarge to 150% safely. We'll see....Show more →

I've found 150% to be just about the upper limit. At 200% I begin to see artifacting. But I've only tested 3 or 4 of the enlargement utilities out there so there might be something better I dunno about - and my tests were limited to only a few samples each as well.

Do let me know if you can tell the difference between 120ppi and 300ppi won't you. I guess you can tell that I think you won't be able to - at arm's length.

Bifurcator wrote:
Do let me know if you can tell the difference between 120ppi and 300ppi won't you. I guess you can tell that I think you won't be able to - at arm's length.

Will definitely do. I'll ping back Thursday, I'm hoping they'll have some samples. Either way, I'm leaving some of my files to get some sections of the images printed (as well as some test prints of smaller images to see the quality of the work).

I'll probably end up getting the prints early next week, I'l definitely update then.

Hi Malux - Test prints of the image (or sections) is the way to go and thanks in advance for sharing you discover later this or next week. A few more things to consider
- The IQ of the image does depend on your viewing distance as the eye has limited resolution so I suggest that the printed test sections of your image be viewed at a distance from which the large print would be viewed
- The test prints need to be on the final print material as each print material has its own characteristics (mentioned by others already) e.g. canvas texture has its own interesting characteristics to the eye yet also hides/limits the resolution one can see where as a glossy can show (and eye expects) to see much more detail.
- Safely printing at larger dimensions has several components and I am assuming that you mean it looks sharp without defects
a) The critical viewing distance is quite important. All other things being equal, viewing 240 to 300ppi at 10 inches will be percieved the same at 120 to 150ppi at 20 inches viewing distance
b) Rule of thumb is that even though there are those that will squish there face close to an image (just as there are those that will critique there images through pixel peeping) a common viewing distance for an image is about the same distance as the diagonal of the image.
c) Enlarging or expanding the pixels can introduce anomalies and this is where the software can play a role. Some are better than others yet it depends on the content of the image. Perfect Resize does well yet so does the newer version of Photoshop (bicubic smoother in PS was already mentioned)
d) Independent of the software is the quality in your pixels to begin with. Quality issues already in your image when enlarged can become more visible (if using the same viewing distance) such as diffraction, anomalous sensor demosaicing artifacts, or just that the shot was not razor sharp in the plane of focus due to limitations of the lens or vibration
e) Not everything in the image is in the plane of focus and if you enlarge the image and view from the same distance, the apparent DOF is reduced. I like to think of DOF more from the eyes limitation point of view. The plane of focus is the only part of the image truly in focus yet due to the eyes limitation, DOF is the distance in front and behind that plane that the eye cannot resolve that it is out of focus and therefore looks sharp. Enlarging the image and viewing from the same distance, the eye is able to resolve more of the image being out of focus and therefore a smaller DOF.
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So expect degradation in your image no mater what you do if you enlarge and view from the same distance. If you are happy with how your image looks at 10"x25" viewing at 10 inches, I be you will be happy with your 20"x50" image when viewed at 20".
Of course this is all my own opinion from my own experience.
Looking forward to what you find out.

You fail to mention the make of printer you are trying to get results from....

If you are an Epson user. The is a company called 'colorbytes' that makes a piece of software called "ImagePrint".

Although very expensive for the casual user. This software starts where plugins like Resize 7 and others leave off. You can go 17 ---> 19 " prints off of a small jepg and stand within inches.. It's used by smaller and medium sized commercial shops. I had it here for 3 years whilst using Espon line but no longer since a switch over to Canon printer system.

The above comments from users (I doubt) have ever used this software.. But it is possible to get remarkable prints with very small files. I have a wall of them.

John Skinner wrote:
.............
If you are an Epson user. The is a company called 'colorbytes' that makes a piece of software called "ImagePrint".

Although very expensive for the casual user. ...........

I would say so. Since the op wants larger than a 30 inch print you would need $2500 software and this is assuming you have a $5000 EPSON printer to go with it. The software is licensed on a per printer basis so definitely targeted for a commercial customer (or someone with deep pockets). Here is the info from their price list:

ImagePrint is sold on a per-printer basis using a concept called "licensing". You'll need one license for each printer that you plan to use with ImagePrint and discounts are available if you license more than one printer. Our licensing is very flexible and you can exchange your current license for a larger or smaller one at any time. Call or email sales for pricing details.
ImagePrint version 9

Thanks for the many thoughts you shared John, I did end up going down to get some test prints today. Here's a few things that came out of this exercise:

1. Even though sending out to lab and having the images show up at your doorstep is great, i will definitely be printing local. It's great to be able to compare what I'm seeing on my screen with what the final print is going to look like with someone who is calibrated from monitor to printer. It's also great to be able to sit down with someone who prints day-in-and-day-out to give you feedback on your images.

2. I need to get my monitors calibrated. I was actually really close in color, but i turn my brightness pretty high up when editing. In the short term, I'd be ok if I turned my brightness low on my monitor, but I will get myself calibrated.

3. For those of you who were wondering: the printer producing my prints is an epson 9890

4. Quoting John:

John Wheeler wrote:
b) Rule of thumb is that even though there are those that will squish there face close to an image (just as there are those that will critique there images through pixel peeping) a common viewing distance for an image is about the same distance as the diagonal of the image.

There's definitely NO place to hide when you print big. We tried a 45" print of one of my images (here's the link to the image by the way.) The original dimensions are 5510x2204. It was shot with a canon 5dii and a 17-40 f/4L. It looked pretty good, but the focus is just a little off (it actually may be motion blur as I was on a dock). It actually looked pretty good, but looking at it, I think that particular image should be on canvas rather than a photo print. I also noticed there are a couple of spots I need to heal/clone (basically lights in the distance). You don't notice them when you print the image at 8x20 (which we also did) but they are definitely distinct at 18x45.

The guy at the shop said I could print the image up to 60". I'm not sure I would do that on photo paper. I also think we could have sharpened the image a bit more to print that big.

With all that said, I'm going to head out to a local gallery and people watch to see how much inspection of images is done. How close do people really get when looking at an image?

5. In terms of answering the question "how big can I print": I think my personal answer is: it depends per image and the only way to know is what others have suggested: print a section and see what it looks like.

6. A couple of other thoughts: i'm not comfortable resizing up at this point, but that's only because i haven't tried to. Something about it just feels like it won't ever be "really" good. Also, about pixel peeping again: i'm going after the fine art market and looking to work with interior designers and art collectors. I only want to show my best images and my best images need to be the best they can be. A bit of pixel peeping (especially considering the large size prints) is warranted. I think i will be ok at 18x45 on photopaper with a sharper image - though canvas is pretty popular as well, and that will help me get to acceptable prints at large sizes.